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A 47-year-old man comes to your ED with complaints of chest pain that radiates to his neck, nausea, shortness of breath (SOB), and weakness on one side of his body. The triage nurse notes that he's diaphoretic, pale, and appears apprehensive. His heart rate is 116 and his BP is 188/104. The patient states that the chest pain occurred suddenly without any precipitating factors. A 12-lead ECG reveals sinus tachycardia. This patient may be experiencing acute aortic syndrome—a term that encompasses aortic dissection, penetrating atherosclerotic ulcer, intramural hematoma, aortic aneurysmal leakage, and ruptured abdominal aortic aneurysm. Can you recognize this life-threatening emergency?

How does it happen?

To understand how an aortic dissection occurs, let's first look at the anatomy of the aorta. The aorta is the largest artery in the body, composed of three layers: inner, middle, and outer. The inner layer—the tunica intima—is a thin, delicate layer in which blood flows through. The middle layer—the tunica media—gives the aorta its strength and elasticity. When this middle layer weakens, the outer layer—the tunica adventitia—swells and forms an aneurysm (see Picturing a dissecting aneurysm).

The pulsing pressure of arterial blood flowing through the aorta continues to weaken the vessel walls, and the aneurysm continues to enlarge further than its normal 2 to 5 cm (0.8 to 2 in) diameter. If the extension continues, the weakened inner layer may tear. This tear will allow the blood to flow freely between the arterial walls, causing a separation or dissection.

Who's at risk?

There are several risk factors for aortic dissection. The majority (over 70%) of patients who experience an aortic dissection have a history of hypertension. The increase pulse pressure of continuous hypertension damages the muscle layers of the aorta, leaving it vulnerable to dissection.

Other risk factors include:

* gender—aortic dissection is three times more common in men than women

* race—Black patients are at increased risk

* age—roughly 75% of aortic dissections occur in people between the ages of 40 and 70, but risk peaks in the 60s and 70s

Diagnosis STAT!

The patient's history is one of the important first steps in trying to establish a diagnosis. It's imperative to consider not only the symptoms, but also the risk factors of high BP, genetic or family history, and the presence of other medical conditions that may predispose the patient to aortic dissection.

Diagnostic tests include:

* 12-lead ECG to rule out acute myocardial infarction (MI)

* chest X-ray, which exposes a widened aorta in up to 90% of patients with an aortic dissection; the chest X-ray reveals no abnormalities in 10% of patients

* computerized tomography (CT) scan of the chest and abdomen is the test of choice for aortic dissection and provides a quick, clear picture of the type and location of the dissection

* magnetic resonance imaging (MRI) reveals the type and extent of the dissection; the MRI takes much longer to perform than a CT scan, diminishing its usefulness

* transesophageal echocardiography(TEE) for unstable patients unable to be transported to radiology

Classify it

The Stanford classification system is the most widely used system to classify aortic dissections. The classification of the dissection will determine the course of treatment. There are two types of dissections:

* type A dissection: a dissection to the ascending aorta that requires surgical intervention

* type B dissection: a dissection of the descending aorta, most often treated medically with routine monitoring and prescribed medications.

In comparison, the DeBakey classification system is based on the site of origin, with type I originating in the ascending aorta and propagating to at least the aortic arch, type II originating in and confined to the ascending aorta, and type III originating in the descending aorta and extending distally or proximally.

Treat it

If the patient is experiencing a type A dissection, emergency surgical intervention is frequently required. The surgery is typically performed as an open procedure, with an incision in the chest or abdomen to provide direct access to the aorta. The area of the aorta with the intimal tear is resected and replaced with a graft to restore blood flow through the aorta. In some cases, the aortic valve may need replacement.

Some patients may be candidates for the minimally invasive approach called endovascular stent graft repair instead of open surgery. In this procedure, a small incision is created in the groin and a stent graft is inserted into the femoral artery. Using fluoroscopy and TEE, the stent graft is guided through the aorta to the aneurysm. After the stent graft is in place, the blood will flow through it instead of through the aneurysm, eliminating the risk of rupture. In order to be a candidate for this procedure, the patient must be in stable condition and the dissection must be located in the descending aorta.

Patients with uncomplicated type B dissections are best treated with drug therapy. The primary goals of drug therapy are the reduction of BP and heart rate, and the control of pain and anxiety. The systolic BP goal is 100 to 120 and the heart rate goal is less than 60. Therapies include beta-blockers for BP and heart rate control, and vasodilators if additional BP control is needed. Titratable beta-blockers, such as esmolol or labetalol, are best, followed by a vasodilator, such as nitroprusside, for optimal BP. If vasodilators are contraindicated, calcium channel blockers, such as verapamil, diltiazem, or nifedipine, may be administered. Opioids, such as morphine sulfate, are given to reduce pain.

What happens next?

Typically, the patient will remain in the hospital for 2 to 10 days, depending on the type of treatment received. Patients who recover from aortic dissection have a 5-year survival rate of up to 80% and a 10-year survival rate of about 50%. After discharge, the patient must be monitored closely for signs and symptoms of late complications, such as another dissection, development of aneurysms in the weakened aorta, and an increase in aortic insufficiency. Long-term management includes aggressive, vigorous BP control. The BP goal is below 120/80 to decrease the force of left ventricular contractions and lower systemic pressure. Beta-blockers are preferred, but calcium channel blockers may be prescribed for patients who can't tolerate them.

To remember what to teach your patient after aortic dissection, use the acronym NOT GOING TO DIE.

* No driving for 1 to 2 weeks

* Only ingest a diet low in sodium and cholesterol

* The importance of maintaining a healthy weight

* Get emergency help if you're experiencing chest pain or other signs and symptoms of dissection

* Only lift things under 10 lb (4.5 kg) for 4 to 6 weeks

* Incision must be kept clean and dry

* Need for repeat CT scan at 1, 6, and 12 months

* Go to your healthcare provider for scheduled appointments

* The importance of aneurysm screening for at-risk family members (particularly those who have hypertension, who smoke, or who are older)

* Observe for any signs and symptoms of dissection

* Don't smoke

* Include daily exercise when cleared by your healthcare provider

* Emphasize the importance of taking medications as prescribed

It's so important to consider the psychological effects that aortic dissection may have on many patients. The fear of another incidence weighs heavily on the mind of the recently diagnosed patient. This devastating feeling is sometimes described like a human time bomb waiting to go off again without warning. The patients who experience this overwhelming feeling of impending doom need to be referred to counseling and support groups.

Wrapping it up

Cardiovascular disease is the leading cause of death in most Western societies. Aortic diseases constitute an emerging share of the burden. An acute aortic dissection is the most common life-threatening disorder of the aorta, affecting nearly 10,000 people per year in the United States. It requires immediate recognition and treatment. If left untreated, about 33% of patients die within the first 24 hours, 50% die within 48 hours, and 75% will die within 2 weeks. You must act quickly to increase the patient's chance of survival; however, the symptoms of aortic dissection are frequently misconstrued for other medical diagnoses. These may include acute MI, pulmonary embolism, stroke, and pericarditis. In fact, 65% of aortic dissections are misdiagnosed, leading to its high mortality.

All patients who've been diagnosed with this condition must be treated with extremely aggressive medical therapy, follow-up visits, and serial imaging. It has been estimated that nearly one third of the patients who survived initial treatment for acute dissection will experience dissection extension or aortic rupture, or will require surgery for aortic aneurysm within 5 years of initial diagnosis. The risk is especially greater in the first few months after initial therapy.

As a nurse, you can play a crucial role in improving the outcome for patients with aortic dissection. Providing lifesaving interventions is possible only when knowledgeable healthcare providers can immediately detect the signs and symptoms of this potentially deadly condition. With aortic dissection, it's crucial to remember that every second counts!